Sheath Provided With A Corrugated Edge For A Pressing Device

ABSTRACT

A sheath for a pressing device, the sheath having a cylindrical circumferential face having a circumferential face radius and an annular bearing resiliently mounted to at least one axial end of the sheath in a spring elastic manner. The annular bearing has a smaller radius than the circumferential face radius. Additionally, the sheath has a bellows-shaped transition region extending at the at least one axial end of the sheath from the cylindrical circumferential face to the annular bearing.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a U.S. National Stage Application ofInternational Application No. PCT/EP2005/051310 filed Mar. 22, 2005,which published as WO 2005/116331 A1 Dec. 8, 2005, the disclosure ofwhich is expressly incorporated by reference herein in its entirety.Further, the present application claims priority under 35 U.S.C. §119and §365 of German Application No. 10 2004 025 944.5 filed May 27, 2004.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a sheath for a pressing device, in particular apaper machine, the sheath surrounding the pressing device at leastpartially and the circumferential face of the sheath havingsubstantially the shape of a cylinder circumferential face, the sheathbeing configured such that it is resilient in a spring-elastic manner.Furthermore, the invention relates to a pressing device having a sheathof this type.

2. Description of Background Information

In modern paper machines, rolls, between which the running material webis guided and is frequently also pressed under high pressure, are oftensurrounded with a flexible sheath which can follow the shape of a shoepress on its circumferential face.

For this purpose, the sheath has to be guided and mounted at its edgeregions on the end sides of the roll, as a result of which these regionsare loaded heavily.

In order to solve this problem, compliant shaped bodies are known whichmake mounting and force transmission possible on the sheathcircumferential face from and to an axially mounted rigid carrier partof the roll.

They have the disadvantage that either the mounting and adjustment arevery complicated and therefore expensive. Furthermore, it isdisadvantageous that the known solutions absorb too much heat from therolling action which occurs as a result of the shapes used and thereforehave to be cooled in a complicated manner, as otherwise the service lifeis reduced considerably.

DE-A 197 03 218 A1 has disclosed a pressing device for a paper machine,in which a circulating roll sheath is mounted rotatably on a rigidcarrier via a radial support device at the axial end regions. Here, theradial support device has a radially elastic hollow torus body, on whichthe roll sheath rests. Here, the torus body is connected fixedly to therigid carrier via a flange by means of a clamping system. The torus bodyis configured separately from the roll sheath, and the roll sheath andtorus body have to be mounted individually on the rigid carrier in acomplicated mounting process and adjusted with respect to one another.

DE-A 101 38 526 A1 has disclosed a flexible pressing sheath with anembedded reinforcement and a shoe press roll with a pressing sheath ofthis type, in which the pressing sheath has an additional reinforcementat its end regions, via which the pressing sheath can be fastened to theouter face of a rotatable support element. This additional reinforcementhas to be incorporated into the pressing sheath in additionalcomplicated manufacturing steps. Furthermore, it is disadvantageous thatthe pressing sheath has to be fastened to the outer face of therotatable support element in an additional mounting step, which makesaccurate and complicated adaptation and adjustment necessary. Complianceof the edge region of the roll surface is not made possible, which hasthe consequence of more pronounced wear and contamination.

DE 35 46 650 C2 has disclosed a press roll sheath which can be clampedand fastened to the end side of the press roll by lugs which are formedintegrally at its axial ends. In this previously known prior art, radialcompliance is not possible at the axial edge region of thecircumferential face, which limits the applicability of the proposedsystem, as only small pressing depths into the press roll surface arepossible.

All the abovementioned solutions have the disadvantage that sealingproblems occur at the transitions of circulating circumferential faceand the end sides of the rolls as a result of the constructions whichare used, which sealing problems can be eliminated only to a limitedextent with high expenditure.

SUMMARY OF THE INVENTION

The invention is based on the aim of making a sheath for a pressingdevice and also a pressing device of this type possible, which sheath isimproved over the prior art and in which the abovementioneddisadvantages do not occur and, in particular, the service life isincreased with respect to the known shapes of sheath.

The invention is directed to a sheath for a pressing device. The sheathsurrounds the pressing device at least partially, the circumferentialface of the sheath has substantially the shape of a cylindercircumferential face, and the sheath is configured such that it isresilient in a spring-elastic manner. The sheath is mounted on anannular bearing at at least one axial end, the radius of the annularbearing is smaller than the radius of the circumferential face, and thesheath extends at the at least one axial end via a bellows-shapedtransition region to the annular bearing. Additionally, the invention isdirected to a pressing device including the above-described sheath for apaper machine.

According to the invention, there is provision for the sheath to bemounted on an annular bearing at at least one axial end, the radius ofthe annular bearing being smaller than the radius of the circumferentialface, the sheath extending at the at least one axial end via abellows-shaped transition region to the annular bearing.

The invention proposes to make a deformation of the sheath, for examplewhen used in a shoe press, reversible in, above all, the radialdirection by the fact that the circumferential face of the sheath ismounted in a reversibly deformable manner and as a result of thebellows-shaped transition region on the annular bearing. For thispurpose, the bellows-shaped transition region is configured with aflexibly deformable bulge which absorbs the mechanical relative movementbetween the circumferential face of the sheath and the annular bearing.

According to one preferred refinement of the invention, there isprovision for the bellows-shaped transition region to be configured inone piece with the circumferential face.

One advantageous refinement of the invention provides for the annularbearing to be formed by the support face of a circular end disk which ismounted axially on the rotating pressing device.

According to one advantageous variant of the invention, there isprovision for the transition region to merge into individual tabs whichare fastened individually to the annular bearing.

A filler body is advantageously provided in the bellows-shaped bulge ofthe transition region between this end of the circumferential face whichadjoins it and the annular bearing.

The filler body is preferably formed by a torus which is halved in theradial direction with regard to its center point.

One advantageous refinement of the invention provides for the fillerbody to seal the inner region of a pressing device which is enclosed bythe sheath, in the region of the transition region.

According to one particularly preferred refinement of the invention, thefiller body is formed by a pressurized tube.

According to one likewise very advantageous variant of the invention,there is provision for the filler body to be formed by a spring-elastictorus body of solid configuration.

Accordingly, the filler body can be of the open-pore configuration, as aresult of which a dissipation of heat is ensured in it as a result ofventilation, which increases the service life.

The pressing device is advantageously filled in the interior with afiller medium at a preselected pressure.

A laid fabric layer is advantageously formed in the sheath, which laidfabric layer extends over the circumferential face and over thetransition region to the annular bearing.

One variant of the invention provides for the laid fabric layer whichextends over the circumferential face to be formed in the sheath.Accordingly, an additional laid fabric layer is provided which overlapswith the laid fabric layer of the circumferential face and extends overthe transition region to the annular bearing.

One advantageous development of the invention provides for theadditional laid fabric layer to be spliced onto the laid fabric layer ofthe circumferential face in the overlapping region.

The circumferential face and the transition region are advantageouslymanufactured from the same material.

The transition region is preferably cast onto or adhesively bonded tothe circumferential face.

The radial compliance of the transition region and the circumferentialface advantageously corresponds at most to 90% of the difference inradius between the circumferential face and the annular bearing.

Further advantages, special features and expedient developments of theinvention result from the further subclaims or their sub-combinations.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following text, the invention will be explained further using thedrawings, in which, in detail and in a diagrammatic illustration:

FIG. 1 shows a diagrammatic view obliquely from above of a pressingdevice 2 according to the invention having a sheath 1 according to theinvention;

FIG. 2 shows a diagrammatic cross-sectional illustration in the axialdirection through the bellows-shaped transition region 3 at the edge ofthe circumferential face 11 of the sheath 1, which edge forms thetransition of the sheath 1 to the annular bearing 7;

FIG. 3 shows a cross-sectional illustration according to FIG. 2 throughthe region which is shown there, the maximum deflection in the directionof the rotational axis being shown;

FIG. 4 shows one refinement of the bellows-shaped transition region 3, alaid fabric which reinforces with respect to tensile forces beingembedded in the sheath 1;

FIG. 5 shows a further refinement of the proposed laid fabric, twodifferent laid fabrics being spliced onto one another in this example;

FIG. 6 shows a diagrammatic cross-sectional illustration according toFIG. 2 through the region shown there, a filler body 5 being providedwhich is provided in the bulge which is formed by the bellows-shapedtransition region 3;

FIG. 7 shows a diagrammatic plan view of the sheath which is used inFIG. 6 and has tab-like extensions for clamping and fastening to the enddisk 6;

FIG. 8 shows a cross-sectional illustration through a furthermodification, in which a torus 51 is provided in the bulge which isformed by the bellows-shaped transition region 3; and

FIG. 9 shows a view in the axial direction of the torus 51 from FIG. 8.

The designations in the figures denote identical or identically actingelements.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a pressing device 2 according to the invention, a shoepress roll of a paper machine, having a sheath 1 according to theinvention.

The sheath 1 merges at its axial ends 17 from the circumferential face11 with a bellows-shaped transition region 3 into the annular bearing 7which is formed by a support on the axially (A) mounted end disk 6 ofthe press roll 2.

FIG. 2 shows a cross-sectional illustration of the bellows-shapedtransition region 3 between the circumferential face 11 of the sheath 1and the annular bearing 7.

The radius R2 of the annular bearing 7 is smaller than the radius R1 ofthe circumferential face 11. As a result, a bulge 32 is formed in theprofile of the bellows-shaped transition region 3.

At one end, the bellows-shaped transition region 3 is integrally formedonto the circumferential face 11 of the sheath 1 and, at its other end,is clamped on the support face 71 in the annular bearing 7 on the enddisk 6.

As the inner region of the press roll which is shown is filled with agas under pressure, the sheath cannot spring back again into itsoriginal shape after passing through the deforming shoe press region(see FIG. 3 in this regard).

FIG. 3 shows the state of maximum deflection of the circumferential face11 of the sheath 1 in the direction of the rotational axis A. Theinitial radius is compressed from R1 to R1 a. The bellows-shapedtransition region 3 firstly keeps the inner region 21 tight and secondlycan transmit force transmission from the rotational axis to thecirculating sheath.

Here, the radial compliance of the transition region 3 and thecircumferential face 11 is at most 90% of the difference in radius(R1−R2) between the circumferential face 11 and the annular bearing 7.

FIG. 4 shows one refinement of the bellows-shaped transition region 3, areinforcing laid fabric 4 which suppresses tensile forces and undesireddeformations being incorporated into the sheath 1 over thecircumferential face 11 to the end of the bellows-shaped transitionregion 3.

FIG. 5 shows one variant of the continuous laid fabric, a first laidfabric layer 41 being incorporated into the sheath 1 along thecircumferential face 11, and a second additional laid fabric layer 43which is selected for the bellows-shaped transition region 3 beingspliced onto the first laid fabric layer 41 in an overlapping region 44.

FIG. 6 and FIG. 7 show a further refinement, the bellows-shapedtransition region 3 of the sheath 1 merging into individual tabs 31which are fastened individually to the annular bearing 7. Furthermore,in the example shown, a spring-elastic filler body 5 which is formed bya tube 52 is provided in the bulge 32 which is formed by thebellows-shaped transition region 3, between the adjacent end 13 of thecircumferential face 11 and the annular bearing 7.

The filler body 5 (tube 52) seals the inner region 21 of the pressingdevice 2 in a gastight manner between the sheath 1 and the end disk 6 atthe bellows-shaped transition region 3. The restoring force of thecircumferential face counter to the deformation at the press shoe cantherefore be set by gas pressure which can be regulated in the interior.

FIG. 7 shows the sheath 1 having the tabs 31 from FIG. 6 which areformed integrally at the axial end 17, in the unwound separate state.

In a modification of FIG. 6, FIG. 8 shows a filler body 5 in the form ofa torus 51 which is halved in the radial direction R with regard to itscenter point.

FIG. 9 shows a view in the axial direction of the torus 51 from FIG. 8.The torus 51 is provided with slots 53. The spring force of thespring-elastic torus 51 can be preselected by the slots 53, in additionto the material selection of the torus 51.

Within the context of the invention, an above-described sheath 1 or apressing device 2 can be used at all locations of the paper machine, atwhich rolls or guides are provided.

LIST OF DESIGNATIONS

-   1 Sheath-   11 Circumferential face of the sheath-   13 Edge region of the circumferential face of the sheath-   17 Axial end-   2 Pressing device-   21 Inner region-   3 Bellows-shaped transition region-   31 Tab-   32 Bulge-   4 Laid fabric layer-   41 Laid fabric layer-   42 Additional laid fabric layer-   44 Overlapping region-   5 Filler body-   51 Torus-   52 Tube-   53 Slot-   6 End disk-   7 Annular bearing-   S End side-   R Radial direction-   R1 Radius-   R2 Radius-   A Axial direction

1-21. (canceled)
 22. A sheath for a pressing device, the sheathcomprising: a cylindrical circumferential face having a circumferentialface radius; an annular bearing resiliently mounted to at least oneaxial end of the sheath in a spring elastic manner, the annular bearinghaving a smaller radius than the circumferential face radius; and abellows-shaped transition region extending at the at least one axial endof the sheath from the cylindrical circumferential face to the annularbearing.
 23. The sheath according to claim 22, wherein the pressingdevice is a paper machine.
 24. The sheath according to claim 22, whereinthe bellows-shaped transition region is structured in one piece with thesheath circumferential face.
 25. The sheath according to claim 22, thepressing device further comprising: a circular end disk mounted axiallyon the pressing device; and a support face on the circular end diskforming the annular bearing.
 26. The sheath according to claim 22,further comprising individual tabs individually fastenable to theannular bearing, wherein the bellows-shaped transition region mergesinto the individual tabs.
 27. The sheath according to claim 22, furthercomprising: a bulge formed by the bellows-shaped transition region; anda filler body arranged in the bulge.
 28. The sheath according to claim27, wherein the filler body is structured in a spring-elasticconfiguration.
 29. The sheath according to claim 27, wherein the fillerbody is provided in the bulge between the edge region and the annularbearing.
 30. The sheath according to claim 27, further comprising atorus halved in a radial direction with regard to a torus center point,wherein the filler body is formed by the torus.
 31. The sheath accordingto claim 27, the pressing device further comprising: an inner region ofthe pressing device; and a circular end disk mounted axially on thepressing device, wherein the filler body seals the inner region of thepressing device, in at least one of an at least partially gastight andan at least partially liquidtight manner, between the sheath and the enddisk at the bellows-shaped transition region.
 32. The sheath accordingto claim 27, further comprising a pressurized tube, wherein the fillerbody is formed by the pressurized tube.
 33. The sheath according toclaim 27, further comprising a spring-elastic torus body of solidconfiguration, wherein the filler body is formed by the spring-elastictorus body of solid configuration.
 34. The sheath according to claim 33,wherein the filler body is of open-pore configuration.
 35. The sheathaccording to claim 33, wherein the filler body is of closed-poreconfiguration.
 36. The sheath according to claim 31, wherein the innerregion is filled with a filler medium at a preselected pressure.
 37. Thesheath according to claim 22, further comprising a laid fabric layerstructured and arranged in the sheath and extending over the sheathcircumferential face and over the bellows-shaped transition region tothe annular bearing.
 38. The sheath according to claim 22, furthercomprising a laid fabric layer structured and arranged in the sheath andextending over the sheath circumferential face
 39. The sheath accordingto claim 38, further comprising an additional laid fabric layeroverlapping the laid fabric layer and extending over the sheathcircumferential face and over the bellows-shaped transition region tothe annular bearing.
 40. The sheath according to claim 39, furthercomprising an overlapping region, wherein the additional laid fabriclayer is spliced onto the laid fabric layer in the overlapping region.41. The sheath according to claim 22, wherein the sheath circumferentialface and the bellows-shaped transition region are composed of a samematerial.
 42. The sheath according to claim 22, wherein thebellows-shaped transition region is one of cast onto and adhesivelybonded to the sheath circumferential face.
 43. The sheath according toclaim 22, wherein a radial compliance of the bellows-shaped transitionregion and the sheath circumferential face corresponds at most to 90% ofa difference between the circumferential face radius and the annularbearing radius.
 44. The sheath according to claim 22, wherein thepressing device is a roll.
 45. The sheath according to claim 22, whereinthe pressing device is a shoe press of a paper machine.
 46. The sheathaccording to claim 22, wherein the sheath at least partially surroundsthe pressing device.
 47. The sheath according to claim 22, wherein thebellows-shaped transition region is arranged between the circumferentialface radius and the annular bearing radius.
 48. A pressing device,comprising: a cylindrical circumferential face having a circumferentialface radius; a sheath having a sheath circumferential face and at leastone axial end; at least one end of the sheath resiliently mounted to anannular bearing in a spring elastic manner, the annular bearing having asmaller radius than the circumferential face radius; and abellows-shaped transition region extending at the at least one axial endof the sheath from the sheath circumferential face to the annularbearing.
 49. The pressing device according to claim 48, wherein thesheath at least partially surrounds the pressing device.
 50. Thepressing device according to claim 48, wherein the bellows-shapedtransition region is arranged between the sheath circumferential faceand the annular bearing.
 51. A method of attaching a sheath to apressing device, comprising: arranging the sheath having a sheathcircumferential face and at least one axial end at least partiallyaround the pressing device having a cylindrical circumferential facehaving a circumferential face radius; resiliently mounting at least oneend of the sheath to an annular bearing in a spring elastic manner, theannular bearing having a smaller radius than the circumferential faceradius; and forming a bellows-shaped transition region extending at theat least one axial end of the sheath from the sheath circumferentialface to the annular bearing.
 52. The method according to claim 51,further comprising arranging a filler body in a bulge formed by thebellows-shaped transition region.